Method of forming one or more metal and/or metal alloy layers in processes for making tranducers in sliders, and related sliders

ABSTRACT

Disclosed herein are methods of forming one or more transducer elements in a transducer region of a slider by electrodepositing one or more metal ions from an ionic liquid solvent, and related sliders.

RELATED APPLICATION

This application is a divisional Patent Application of nonprovisionalpatent application Ser. No. 15/231,272, filed Aug. 8, 2016, which isincorporated herein by reference in its entirety.

FIELD

The present disclosure relates to computer hard disk drive transducerheads, and related methods of making. In particular, the presentinvention relates to transducer heads having a write head and/or readhead formed at least in part via electrodeposition of a metal or metalalloy from an ionic liquid.

BACKGROUND

Computer hard disk drives can store information on magnetic disks. Theinformation can be stored on each disk in concentric tracks, dividedinto sectors. The information can be written to and read from a disk bya transducer head, mounted on an actuator arm capable of moving thetransducer head radially over the disk. Accordingly, the movement of theactuator arm allows the transducer head to access different tracks. Thedisk can be rotated by a spindle motor at a high speed, allowing thetransducer head to access different sectors on the disk.

There is a continuing desire for new and/or improved transducer heads,and related methods of making such heads.

SUMMARY

In some embodiments of the present disclosure is a method of plating ametal or metal alloy onto a wafer to form one or more transducerelements, wherein the method comprises:

a) providing a wafer comprising two or more layers of material, whereinat least one of the layers comprises a patterned layer for forming oneor more transducer elements in the wafer, wherein the pattern comprisesone or more cavities in a major surface of the patterned layer;

b) electrodepositing one or more metals from a non-aqueous compositioninto at least a portion of the one or more cavities to fill at least theone or more cavities thereby defining at least a portion of the one ormore transducer elements, wherein the non-aqueous composition comprisesan ionic liquid solvent and one or more metal salts dissolved in theionic liquid solvent, wherein the ionic liquid solvent comprises acation and anion.

In other embodiments of the present disclosure is a slider bodycomprising:

-   -   a first side face;    -   a second side face;    -   an air bearing face, wherein the air bearing face comprises a        leading edge and a trailing edge, wherein the air bearing face;        comprising a transducer region comprising one or more transducer        elements, wherein at least one of the transducer elements        comprises a metal alloy comprising at least one of titanium or        tantalum; and    -   a trailing edge face that is adjacent to the trailing edge of        the air bearing face.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top view of a portion of a prior art computer disk drive,with the cover removed;

FIG. 2 is a cross-sectional view of a prior art transducer head;

FIG. 3 is one embodiment of a flow diagram showing multiplecross-sectional views of forming plating a metal or metal alloy onto awafer;

FIG. 4 is another embodiment of a flow diagram showing multiplecross-sectional views of forming plating a metal or metal alloy onto awafer; and

FIG. 5 is another embodiment of a flow diagram showing multiplecross-sectional views of forming plating a metal or metal alloy onto awafer.

DETAILED DESCRIPTION

The present disclosure is in the context of plating a metal or metalalloy from an ionic liquid onto a wafer to form one or more transducerelements, and related sliders.

An example of a computer disk drive is illustrated in FIG. 1. The diskdrive 20 includes a base 24 and one or more magnetic disks 28 (only oneof which is shown in FIG. 1). As shown, the magnetic disks 28 areinterconnected to the base 24 by a spindle motor (not shown) mountedwithin or beneath the hub 32, such that the disks 28 can be rotatedrelative to the base 24. As shown, actuator arm assemblies 36 (only oneof which is shown in FIG. 1) are interconnected to the base 24 bybearings 40, such that they can be moved radially with respect to themagnetic disks 28. The actuator arm assemblies 36 include sliders (orslider bodies) 44 (only one of which is illustrated in FIG. 1) at afirst end, to address each of the surfaces of the magnetic disks 28. Aslider body includes transducer elements. A slider body 44 includes afirst side face; a second side face; an air bearing face; and a trailingedge face. The air bearing face includes a leading edge, a trailingedge, and a transducer region including one or more transducer elements.The trailing edge face is adjacent to the trailing edge of the airbearing face.

Exemplary transducer elements that can be formed using ionic liquidsolvent plating techniques described herein include one or more of awrite pole, a writer shield, a reader shield, combinations of these, andthe like.

As shown in FIG. 1, a voice coil motor 48 can pivot the actuator armassemblies 36 about the bearings 40, to radially position a slider 44across the surfaces of the magnetic disks 28. The voice coil motor 48can be operated by a controller 52 that is in turn operatively connectedto a host computer (not shown). By changing the radial position of aslider body 44 with respect to the magnetic disks 28, the transducerelements in a slider body 44 can access different data tracks orcylinders 56 on the magnetic disks 28.

An example of a transducer region 100 is illustrated in FIG. 2, andincludes a write head 104 and a read head 108. The write head 104 isknown as an inductive head. Where such heads are constructed fromferrite material, they are known as ferrite heads. As shown, write head104 includes a yoke of magnetically conductive material formed from awrite pole 112 and a shared shield 116. As shown, a coil of electricallyconductive wire 118 is wrapped about a portion of the yoke, and the endsof that coil are connected to a current source (not shown). During awrite operation, current is introduced to the coil in a first direction.The electrical current through the coil produces a magnetic field withinthe yoke. At a gap 120 formed between an end of the write pole 112 andan end of the shared shield 116, the magnetic field spreads out becausethe magnetic permeability of the gap is less than that of the yokeitself. The gap 120 is positioned so that it is in close proximity tothe magnetic disk, allowing some of the magnetic field to pass throughthe disk and magnetize a portion of the disk in a particular direction.In some embodiments, a disk drive for use in a digital computer, a “one”can be coded by reversing the direction in which the disk is magnetizedfrom one portion of a track to the next. This can be done by reversingthe direction of the current in the coil. A zero can be indicated by theabsence of a change in magnetic polarity. Of course, this protocol couldbe reversed.

The read head 108 in a disk drive can operate by sensing the magneticflux transitions encoded in the disk by the write operation. One methodof sensing such transitions is with a magnetoresistive head. Such a headcan be made of material that changes its electrical resistance when itis exposed to a magnetic field. Magnetoresistive heads have come intowide use in disk drive systems because they are capable of providinghigh signal output. High signal output can be desirable, because themagnetic fields produced in the disks by the write operation can berelatively very small. In addition, the high signal output of themagnetoresistive head can allow the data on the disk to be denselypacked, allowing the disk drive to have a high storage capacity.

Magnetoresistive read heads can include a strip of magnetoresistivematerial 124 held between two magnetic shields. As shown in FIG. 2, themagnetic shields are formed from the shared shield 116 and a read shield128. Each end of the strip of magnetoresistive material 124 is connectedto a conductor (not shown). The conductors are in turn can be connectedto a current source (not shown). Because the electrical resistance ofthe magnetoresistive material can vary with the strength and directionof an applied magnetic field, magnetic flux transitions result inchanges in the voltage drop across the magnetoresistive strip. Thesechanges in the voltage drop are sensed and then converted into a digitalsignal for use by the host computer.

In order to sense the transitions between the small magnetic fields andthus retrieve data from the magnetic disk, the magnetoresistive readhead 108 can be held in close proximity to the track containing thedesired information. The disk 28 can be rotated under the head 44, andflux transitions read by the head 44 can be interpreted as a binary“one”, as described above. The magnetic shields on either side of themagnetoresistive material 124 can limit the effect of magnetic fluxtransitions adjacent to or in the proximity of the precise area of thetrack from which information is to be retrieved. In some embodiments,one pole of the inductive write head also serves as part of the shield.In some embodiments, this shared shield can be about 1-3 μm thick.

Embodiments of the present disclosure are related to forming one or moretransducer elements in a slider. In particular, embodiments of thepresent disclosure are directed to a method of plating a metal or metalalloy onto a wafer to form one or more transducer elements byelectrodepositing one or more metals from an ionic liquid. Exemplaryembodiments of the present disclosure are illustrated as process 300 inFIG. 3, process 400 in FIG. 4, and process 500 in FIG. 5, which figuresare described throughout herein below.

Methods of the present disclosure include providing a wafer for formingone or more transducer elements thereon. In some embodiments, a waferincludes two includes two or more layers of material. Examples of awafer are illustrated in FIGS. 3-5. As shown in FIG. 3, the waferincludes a layer 310 and a layer 320. As shown in FIG. 4, the waferincludes a layer 410 and layer 420. As shown in FIG. 5, the waferincludes a layer 510 and layer 515. One or more layers of a wafer can bemade out of a variety of materials. In some embodiments, layer 310,layer 410, and layer 510 can be made out of a two phase mixture ofalumina and titanium-carbide (AlTiC). Layers 310, 410, and 510 can havea range of thicknesses, e.g., from 0.1 to 5 mm, from 0.5 to 3 mm, oreven from 1 to 2 mm.

As used herein, a “wafer” can be processed to form a plurality ofsliders (read/write heads). After processing a wafer as describedherein, the wafer can be subsequently processed (e.g., slicing anddicing operations) to divide the wafer into individual sliders.

At least one of the layers of the wafer includes a pattern (i.e., “apatterned layer”) to form one or more transducer elements in the wafer.As shown in FIG. 3, layer 320 includes a pattern defined by cavities 326in the major surface 325, thereby forming a patterned layer 320. Asshown in FIG. 4, layer 420 includes a pattern defined by cavities 426 inthe major surface 425, thereby forming a patterned layer 420. Theremainder of process 500 in FIG. 5 is further discussed below.

A patterned layer can be formed by a variety of techniques. In someembodiments, a patterned layer can be formed using photolithography. Anexample of such a method is illustrated with respect to FIG. 4. In FIG.4, a layer 416 is formed over layer 410. Such a layer can be formed intowhat is referred to as a “hard mask” 420. A layer 416 can be made out ofa variety of materials, e.g., one or more dielectric materials. Specificexemplary materials include alumina or silicon dioxide.

Optionally, as shown in FIG. 3, basecoat layer 315 (e.g., alumina) canbe included over layer 310. Similarly, as shown in FIG. 4, basecoatlayer 415 can be included between layer 410 and layer 416. In someembodiments, the basecoat layer 410 can be made of the same material asthe layer 416. For example, both layer 415 and layer 416 can be made outof alumina.

Next, a pattern 417 can be formed over the layer 416. The pattern 417includes openings 418 that expose a surface of the underling layer 416.The pattern 417 can be formed using photolithography and can be made outof a metal material so as to stand up to ion milling. After formingpattern 417, the exposed surfaces of the layer 416 can be etched throughthe layer 416 to form patterned layer 420 (also referred to a “damascenemask”). After the layer 416 has been etched, the material 417 can beremoved. The material 417 can be removed at one or more points in theprocess shown in FIG. 4. For example, as shown in FIG. 4, material 417can be removed directly after forming cavities 426 via reactive ionetching (“rie”). Alternatively (not shown in FIG. 4), the material 417can be removed in the last step (discussed below) when a portion of thelayer 430 that overlies the major surface 425 of the patterned layer 420is removed to define at least a portion transducer elements 440 and 441.

Optionally, an electrically conductive layer can be provided over thepatterned layer so that the electrically conductive layer conforms totopography of the patterned layer to facilitate plating a metal or metalalloy. Although not shown in FIG. 3, an electrically conductive layercan be present on at least the bottom surface of cavities 326. Anembodiment where an electrically conductive layer is present on only thebottom of a cavity is illustrated in FIG. 5, which is discussed below.Optionally, the side walls of cavities 326 can also include anelectrically conductive layer. For example, as shown in FIG. 4, anelectrically conductive layer 427 can be provided over the patternedlayer 420 so that the electrically conductive layer conforms totopography of the patterned layer 420.

In some embodiments, the electrically conductive layer 427 has athickness in the range from 100 angstroms to 3000 angstroms, or evenfrom 200 to 1000 angstroms. In some embodiments, the electricallyconductive layer 427 can be made out of the same material as atransducer element.

Next, one or more one or more metals can be electrodeposited from anon-aqueous composition onto at least a portion of a patterned layer toform a layer of metal (e.g., elemental metal) or metal alloy adjacent tothe major surface of the patterned layer. The non-aqueous compositionincludes an ionic liquid solvent and one or more metal salts dissolvedin the ionic liquid solvent. A non-aqueous composition refers to acomposition that is not aqueous-based like aqueous compositions used inmany known electrodeposition techniques. The non-aqueous composition isbased on an ionic liquid as a solvent or electrolyte in which toelectrodeposit one or more metals therefrom.

As used herein, “ionic liquid solvent” means a liquid that is capable ofbeing produced by melting a solid at or below 100° C. An ionic liquidsolvent can consist solely of ions (e.g., at least one cation and atleast one anion). Ionic liquids may be derived from inorganic and/ororganic salts. Accordingly, an ionic liquid cation can include anorganic cation (e.g., pyrrolidinium, imidazolium, ammonium) and/or aninorganic cation, and an ionic liquid anion can include an organic anionand/or an inorganic anion (e.g., chloride, bromide, triflate,tetrafluoroborate). Ionic liquid solvents are different from aqueoussolvents, organic solvents, and high temperature molten salts.

In some embodiments, an ionic liquid solvent includes a halometallateionic liquid solvent. Halometallate ionic liquid solvents refer to aclass of ionic liquid solvents that include an organic halide, usuallywith an organic cation such as imidazolium or pyridinium, and a Lewisacid metal halide. For example, an organic chloride and AlCl₃ can becombined to form a chloroaluminate ionic liquid solvent. Inhalometallate ionic liquid solvents, a Lewis acid can tend to associatewith an anion of the ionic liquid to form a Lewis acid anion. In someembodiments, a higher molar ratio of Lewis acid to organic halide cangive a Lewis acidic system, and a lower molar ratio of Lewis acid toorganic halide can give a Lewis basic system.

In some embodiments, an ionic liquid solvent can include a deep eutecticsolvent, which is a eutectic mixture of a quaternary ammonium halide,and an inorganic metal salt or an organic hydrogen-bound donor (e.g., anamide or an alcohol). An exemplary deep eutectic solvent includes amixture of choline halide (e.g., chloride) and urea.

Salts and oxides of one or more metals can be dissolved in an ionicliquid. In some embodiments, for example when using a halometallateionic liquid, variations in Lewis acidity can change the electrochemicalproperties of the system. This feature can facilitate the proportions ofco-deposited metals to be controlled.

As mentioned, in some embodiments, one or more metal salts can bedissolved in an ionic liquid. Exemplary metal salts include a metalhalide, a metal sulfate, and mixtures thereof. In some embodiments, ametal salt can include a nickel salt, an iron salt, a cobalt salt, atantalum salt, a titanium salt, a magnesium salt, a palladium salt, anindium salt, a gallium salt, an antimony salt, a tellurium salt, acadmium salt, a copper salt, a zinc salt, a tin salt, a germanium salt,a silicon salt, an aluminum salt, a noble metal salt, and mixturesthereof.

Optionally, one or more additives can be included in the ionic liquidsolvent to facilitate plating and/or the properties of the platedmaterial (e.g., morphology, mechanical properties, and/orelectrochemical properties). Exemplary optional additives include one ormore of acetonitrile, coumarin, thiourea, benzotriazole, and acetone.

Either an elemental metal can be electrodeposited from an ionic liquidor a metal alloy can be electrodeposited from an ionic liquid bysimultaneously electrodepositing two or more different metals from anionic liquid. Accordingly, a deposited metal or metal alloy (andcorresponding transducer element) could include one or more of thecorresponding metals from the corresponding salt such as nickel, iron,cobalt, tantalum, titanium, aluminum, and a noble metal (e.g., gold,silver, or platinum).

While not being bound by theory, it is believed that metals and/or metalalloys electrodeposited from an ionic liquid may have one or more bettermechanical/physical properties as compared to the same metal or metalalloy deposited from an aqueous solution. For example, due to thepresence of hydrogen ions in solution during aqueous electrodeposition,competing reactions can occur at the cathode as well as metal ionreduction. Hydrogen reduction is a competing reaction and can result inhydrogen embrittlement (hydrogen trapped in the deposit). Hydrogenembrittlement can cause a brittle deposit. Stresses can be unduly highin deposits where hydrogen has been trapped. Also, current efficiencycan drop when other species other than the target metal ion or metalions are reduced at the cathode surface. Further, plating rate can dropwith a reduction in current efficiency, thereby causing wafer cycletimes to go up with corresponding longer plating times. Accordingly, itis believed that metals and/or metal alloys electrodeposited from anionic liquid can avoid such issues involved with aqueous solutions.

Also, while not being bound by theory, it is believed that metals and/ormetal alloys (e.g., NiFe, CoNiFe and CoFe) formed from an ionic liquidas opposed to using aqueous chemistry can have one or more improvedphysical and magnetic properties such as lower coercivity (softness),lower stress, reduced grain size, less impurities, lower porosity,increased corrosion resistance (e.g., no sulphur inclusions from platingbath additives) and lower cycle time.

While not being bound by theory, it is believed that metals that may bedifficult or practically impossible to electrodeposit from aqueoussolutions can be electrodeposited from an ionic liquid. Some metals canbe challenging to electrodeposit from aqueous chemistry because theNernst potential of such metals is below that at which water decomposes.Accordingly, metals such as tantalum (Ta), magnesium (Mg), titanium(Ti), and/or aluminum (Al) could be plated via an ionic liquid solventaccording to the present disclosure with one or more other metals toenhance one or more properties such as corrosion resistance. As anotherexample, a noble metal such as gold (Au) may be able to be depositedwith a magnetic metal like iron (Fe) to form an alloy.

A non-aqueous composition can be formed by mixing an ionic liquidsolvent and one or more metal salts. A salt can be provided in an ionicliquid solvent in a concentration so as to provide the desired amount ofmetal on a substrate after plating. By using an ionic liquid solvent, itis believed that the amount of metal in the ionic liquid solvent can berelatively close to the amount of metal plated onto a substrate,especially as compared to using aqueous chemistry. In some embodiments,the concentration of a metal salt in an ionic liquid solvent can be inthe range from 0.001 to 10 M, from 0.005 to 5M, or even from 0.05 to 3M.Also, by using an ionic liquid solvent, it is believed that the amountof two or more metals in the ionic liquid can be relatively close to theamount of the two or more metals plated onto a substrate, especially ascompared to using aqueous chemistry. For example, the presence of somemetals can reduce the amount of another metal that is plated out ofsolution in aqueous chemistry so the amount of the other metal in theaqueous solution is often increased to achieve the desired amount platedonto a substrate. Using an ionic liquid solvent may facilitate platingthe out relatively more of the other metal. In some embodiments, theweight ratio of the concentration of one metal salt to a second metalsalt in an ionic liquid solvent can be in the range from 0.3 to 0.7, oreven from 0.4 to 0.6.

A variety of electrodeposition techniques can be used to plate a metalor metal alloy (electrocodeposition) from an ionic liquid solvent.Different techniques can use different sources for providing electronsto reduce metal ions present in an ionic liquid solvent. One example isto provide a power source as a source of reducing electrons. A source ofelectrons can be constant or dynamic. For example, galvanostatic plating(DC plating) can utilize a constant current density as a source ofreducing electrons. DC plating can advantageously to help provide ametal coating with uniform composition. Another example of a powersource as a source of reducing electrons includes potentiostaticconstant voltage plating. Another example of a power source as a sourceof reducing electrons includes galvanodynamic plating, which pulses acurrent as desired. Galvanodynamic plating can advantageously facilitatecontrolling grain size. Yet another example of a power source as asource of reducing electrons includes potentiodynamic voltage plating,which switches the voltage from on to off as desired.

Elecrodepositing elemental zirconium from an ionic liquid is disclosedin U.S. Pat. No. 9,017,541 (Seddon et al.), the entirety of which patentis incorporated herein by reference.

Electrodeposition can occur when the non-aqueous composition is at atemperature in the range from 0° C. to less than 100° C., from 15° C. to50° C., or even from 20° C. to 35° C.

Electrodeposition can occur for a time period in the range from 30seconds to one hour, from 5 minutes to 30 minutes, or even from 10minutes to 20 minutes.

Electrodeposition can include a working electrode (e.g., a wafer havinga patterned layer) and a counter electrode. The counter electrode may bemade from a metal (e.g., platinum), a semiconductor or glassy carbon. Insome embodiments, a third electrode (e.g., silver) can be included as areference electrode.

Referring to FIG. 3, one or more metals are electrodeposited from anon-aqueous composition onto at least a portion of the patterned layer320 to form a layer 330 of metal or metal alloy adjacent to the majorsurface 325 of the patterned layer 320. As shown, the metal or metalalloy of layer 330 fills one or more cavities 326 in the major surfaceof the patterned layer 320. Similarly, referring to FIG. 4, one or moremetals are electrodeposited from a non-aqueous composition onto at leasta portion of the patterned layer 420 to form a layer 430 of metal ormetal alloy adjacent to the major surface 425 of the patterned layer420. As shown, the metal or metal alloy of layer 430 fills one or morecavities 426 in the major surface of the patterned layer 420. Althoughnot shown, in some embodiments, the portion of layer 430 overlyingapproximately the centers of cavities 426 can be relatively depressed soas to form a “pothole” like topography on the three-dimensional surfaceof layer 430. While not being bound by theory, it is believed thatduring plating the sidewalls of cavities having conductive materialthereon such as in FIG. 4 can contribute to the formation of suchpothole like topography. In some embodiments, to help reduce suchplating consequences a polymer (e.g., a glycol-based polymer) coatingcan be applied to the cavity sidewalls so as to hinder plating on thesidewalls so that plating from the bottom of the cavity dominates thefilling of a cavity.

Next, at least a portion of the layer of metal or metal alloy thatoverlies the major surface of the patterned layer can be removed suchthat the metal alloy remains in the one or more of the cavities todefine at least a portion of the one or more transducer elements. Forexample, as shown in FIG. 3, a portion of the layer 330 that overliesthe major surface 325 of the patterned layer 320 can be removed suchthat the metal or metal alloy remains in the one or more of the cavities326 to define at least a portion of transducer elements 340 and 341. Asshown in FIG. 4, a portion of the layer 430 that overlies the majorsurface 425 of the patterned layer 420 can be removed such that themetal or metal alloy remains in the one or more of the cavities 426 todefine at least a portion of transducer elements 440 and 441.

Transducer elements 340, 341, 440, and 441 generically represent atleast a portion of an exemplary transducer element such as a write pole,a writer shield, a reader shield, combinations of these, and the like.

Next, the remainder of process 500 in FIG. 5 is discussed. Instead offorming cavities (vias) in a layer such as 420 and then plating a metalor metal alloy in such cavities 426, cavities can be formed usingphotoresist material as shown in FIG. 5. As shown in FIG. 5, anelectrically conductive layer 527 can be provided over basecoat 515. Asdescribed below, 515 can be built up around a transducer element 530after forming the transducer element. Basecoat 515 can be made out of avariety of materials, e.g., one or more dielectric materials. Specificexemplary materials include alumina or silicon dioxide. As also shown inFIG. 5, a photoresist layer 517 is formed on electrically conductivelayer 527 so as to form a pattern of cavities such as cavity 526. Byforming photoresist layer on electrically conductive layer 527, only thebottom of cavity 526 has electrically conductive layer 527 to facilitateplating a metal or metal alloy. Such a strategy can avoid forming thepothole topography as described above with respect to FIG. 4.

Accordingly, as shown in FIG. 5, one or more metals are electrodepositedfrom a non-aqueous composition into the cavities 526 of the patternedlayer 517 to form transducer elements 530. After forming transducerelements 530, the photoresist material 517 can be stripped away down tobasecoat 515, followed by additional basecoat material so as to form alayer 515 that is approximately level with the top surface of transducerelement 530.

Transducer elements 530 generically represent at least a portion of anexemplary transducer element such as a write pole, a writer shield, areader shield, combinations of these, and the like.

What is claimed is:
 1. A slider body comprising: a first side face; asecond side face; an air bearing face, wherein the air bearing facecomprises a leading edge and a trailing edge, wherein the air bearingface comprises a transducer region comprising one or moremagnetoresistive, transducer elements, wherein at least one of themagnetoresistive, transducer elements comprises a metal alloy comprisingtwo or more different metals, wherein the two or more different metalscomprise at least one of titanium or tantalum; and a trailing edge facethat is adjacent to the trailing edge of the air bearing face.
 2. Theslider body of claim 1, wherein the one or more transducer elements ischosen from a write pole, a writer shield, a reader shield, andcombinations thereof.
 3. The slider body of claim 1, wherein the one ormore transducer elements are surrounded by one or more dielectricmaterials.
 4. The slider body of claim 1, wherein the one or moredielectric materials are chosen from alumina or silicon dioxide.
 5. Ahard disc drive comprising one or more slider bodies according toclaim
 1. 6. The slider body of claim 1, wherein the two or moredifferent metals further comprise at least one metal chosen from nickel,cobalt, iron, aluminum, a noble metal, and combinations thereof.
 7. Theslider body of claim 6, wherein the noble metal is chosen from gold,silver, platinum, and combinations thereof.
 8. The slider body of claim1, wherein the two or more different metals further comprise at leastaluminum.
 9. The slider body of claim 1, wherein the two or moredifferent metals further comprise a noble metal.